Researches on the Grall-flies of the Oak. 281 
exceeds 8 lines (17 millim.), One specimen inhabited a shell 
of a species of Clavatula. 
I cannot regard the distinctions mentioned by Heller as 
characteristic of H. meticulosus as of specific importance. 
The smallest specimen in the collection referred to this 
species—leneth of carapace not 3 lines (6 millim.)—has the 
outer surface of the palm in the larger chelipede much more 
evenly granulated and the median longitudinal ridge obsolete, 
and bears a great resemblance to H. Horbesi, Heller, of which 
there is an authentically named specimen from Falmouth 
(W. P. Cocks, Hsq.) in the Museum collection, which may be 
nothing but the young state of this species. I hesitate, how- 
ever, to unite the two without further comparison of a larger 
series of specimens. A much larger example from Sicily, in 
the Museum collection, designated H. Forbesi, has the outer 
surface of the larger chela armed with numerous spines, and 
without depressions or longitudinal ridges, and is probably 
referable to H. Lucast, Heller (=£. spinimanus, Lucas). 
Besides the Paguridee enumerated above, there is in the col- 
lection a very small hermit-crab, apparently of the genus 
Cibanarius, inhabiting a sheil of Nassa miga, Adanson, 
which it would be unadvisable to designate by a distinct 
specific name. 
[To be continued. | 
XXVII.—Dr. H. Apuur’s* Researches on the Alternating 
Generation of the Gall-flies of the Oak. 
“ A SATISFACTORY explanation of the mode of reproduction of 
the Cynipidee will only be obtained when their development 
is traced step by step, through all its stages, from the ferti- 
lized and unfertilized egg. Let us hope that amongst our 
entomologists an Qidipus will be found able to solve this 
enigma.” 
It was thus that Prof. von Siebold expressed himself in the 
last chapter of his work upon parthenogenesis, published 
ten years ago. The Cidipus has appeared, and has furnished 
us with one of the most curious chapters in the history of 
insects. 
It has been known for a long time that in many species 
* Translated by W. Francis, jun., from the ‘ Bibliothéque Universelle 
de Genéve’ for June 15, 1881. 
